export interface TreeItem{
    id:string|number,
    parentId:string|number,
    name:string,
    allowChecked?:boolean,//是否出现勾选框
    checked?:boolean,//是否勾选上
    open?:boolean,//是否展开
    children?:TreeItem[]
    [key: string|number|symbol]: any;//一些附带的值，非树组件需要的值
}